CLINTON, Iowa (AP) - Mitt Romney has stepped into the center of a perfect storm in Iowa -- and he's going all in.

Sensing an opening to win next Tuesday's caucuses, an ever-more confident Romney is campaigning hard in a region of the state where he performed well in his failed 2008 race, with a bus tour and new crush of advertising intended to bolster his closing argument: that he's the most electable candidate against President Barack Obama.

It's thanks to a combination of luck and planning that Romney now finds himself in strong contention for an Iowa caucus victory that would give him a boost heading into the next contest, in New Hampshire, where the former Massachusetts governor's standing is strong.

Not that he's publicly entertaining the notion of back-to-back victories.

"I can't possibly allow myself to think in such optimistic terms. I just have to put my head down and battle as best I can," Romney said Wednesday. "But I can tell you: If the people here in Clinton are any example, or any indication, of what's going to happen in the process, I feel pretty good."

In a sign of his growing confidence that a victory may be at hand, Romney plans to spend caucus night in Iowa.

Advisers are redoubling efforts to try to capitalize on the slide in support for Newt Gingrich and skepticism of Ron Paul by making a concerted effort to increase turnout in areas where Romney did well four years ago. His campaign also added at least $100,000 in additional advertising for the final days -- and bought broadcast advertising for the first time in the Quad Cities market in eastern Iowa.

And, while Romney is largely shying away from criticizing his rivals, he jabbed at Paul, who has emerged as his chief rival in Iowa, on Wednesday -- another indication of Romney's efforts to triumph here.

"One of the people running for president thinks it's OK for Iran to have a nuclear weapon," Romney said in Muscatine in response to a question from the audience. "I don't."

This is a far more aggressive strategy than the one Romney has employed all year after pouring $10 million into the state in 2008 only to lose it in a defeat that crippled his entire campaign. He couldn't allay concerns about his Mormon faith or his reversals on some social issues in a state where evangelical Republicans and other social conservatives dominate.

Romney approached Iowa more cautiously for this race, so much so that until recently aides worked out of an attic in Des Moines on a shoestring budget. He also had spent less than $200,000 on the state before the campaign started buying TV ads in December.

But even as advisers worked to play down expectations, they quietly stayed in contact with backers from his first campaign -- and Romney stood at the ready to try to take advantage of an opportunity in the race, should one present itself.

It looks like it has.

Social conservatives that united behind former Arkansas Gov. Mike Huckabee in 2008 remain splintered among a handful of candidates that include Texas Gov. Rick Perry, Minnesota Rep. Michele Bachmann and former Pennsylvania Sen. Rick Santorum. Gingrich, the former House speaker, was Romney's latest threat but he's taken a significant beating from an onslaught of advertisements by a super PAC run by Romney's allies. Paul, a libertarian-leaning Republican, is a serious contender in Iowa but he has foreign policy views so outside the Republican mainstream that most Republicans believe he has little chance to win the GOP nomination.

On Wednesday, a new CNN/TIME poll in Iowa showed Romney leading with 25 percent support. Paul had 22 percent and Santorum drew 16 percent while Gingrich had fallen to 14 percent.

So Romney is trying to seize the moment. And it may be working.

Overflow crowds have been greeting Romney at every stop of his three-day, seven-city tour on a bus plastered with his campaign logo and "Conservative, Businessman, Leader" slogan on the side.

So many people showed up at a deli in Clinton that Romney's staff also sent the candidate to visit the restaurant across the street. Before sunrise, the line to see Romney at Elly's Coffee and Tea in Muscatine stretched out the door and down the block.

On Tuesday night, the campaign said that only 150 people had RSVPed to attend Romney's speech in Davenport. But more than 500 people showed up, shutting at least 200 people out of the Blackhawk Hotel ballroom. Many area voters were notified only that morning of Romney's visit.

People seem to like what they hear.

"He's probably the best chance to beat Obama," said Carol Hetzler, a medical secretary who backed Sen. John McCain's in 2008. She had also considered voting for Gingrich.

And Tim McCleary, who was waiting in line at Elly's before 7 a.m. to see Romney, said: "The only reason I'm supporting Romney is because he can win the election."

As Romney visits small towns in eastern Iowa, he's also doing countless interviews with the local media. He spent most of Wednesday morning talking to radio stations and small Iowa newspapers.

He's also relying on friends to help him make the sale.

Romney was dispatching surrogates from nearby states, including South Dakota Sen. John Thune, former Sens. Norm Coleman of Minnesota and Jim Talent of Missouri, to campaign in Iowa. Former Kansas Sen. Bob Dole was dialing influential activists Tuesday, including former state GOP chairman Steve Grubbs, who is a well-connected campaign operative in Davenport in the heart of Romney's eastern Iowa base.

"He made the argument that the candidate who has shown the ability to win by the effectiveness of the campaign he's run is Mitt Romney," said Grubbs, who worked on Dole's 1996 campaign. "At the end of the day, he was selling electability."

It's the case Romney will try to make in North Liberty, Waterloo and Ames on Thursday and in Des Moines on Friday.

Mindful not to ignore New Hampshire altogether, Romney planned events there Friday and Saturday. Four of his five sons will campaign in the state Thursday before heading to Iowa this weekend. His wife, Ann, will remain in Iowa all weekend, campaigning in the western part of the state. Romney returns to Iowa later Saturday.